1. Field of the Invention
This invention relates to refractory metal carbides. More particularly, it relates to refractory metal carbides which have a layer of cobalt over the surfaces and metallurgically bonded to the surfaces of the refractory metal carbide.
2. Prior Art
In U.S. Pat. No. 2,979,811 there is disclosed a method by which some of the cobalt used to cement carbide bodies together migrates to the surfaces of the refractory metal carbide thereby increasing the wettability of the surfaces. In general, the method disclosed in that patent consists of heating the refractory metal carbide to a temperature of 950.degree.F to 1250.degree.F by immersion in a salt bath followed by quenching it in a salt bath at a temperature of approximately 1100.degree.F and thereafter further quenching it in oil or water. The high temperature bath is disclosed as barium chloride and the quenching bath is disclosed as being a mixture of sodium cyanide, potassium chloride and potassium cyanate. The purpose of obtaining a cobalt coating on a refractory metal carbide is to enable the refractory metal carbide to be brazed to other bodies. Such brazing is highly satisfactory wherein carbide tool tips are brazed to metal. Drilling tools, saw blades, snowmobile runners and the like utilize the foregoing concept. While the process disclosed in the foregoing patent can produce a material capable of being brazed to another body, it is believed apparent that high temperatures and the salt bath used to initially heat the body in a cyanide-containing quenching bath affords drawbacks from a processing standpoint and does not strengthen the body since some of the cobalt used as a binder migrates to the surface. It is believed, therefore, that a process which provides an improved coating and enables more conventional processing temperatures and less hazardous materials to be utilized would be an advancement in the art.